1. Field of the Invention
The present invention relates to keyless entry apparatuses, and more particularly, to a keyless entry apparatus for controlling a member to be controlled of a vehicle by an answer signal which a portable transmitting and receiving device transmits when the portable transmitting and receiving device receives a request signal transmitted from an on-vehicle transmitting and receiving device.
2. Description of the Related Art
Each of conventional keyless entry apparatuses is formed of an on-vehicle transmitting and receiving device mounted on a vehicle and a portable transmitting and receiving device carried by a user. The on-vehicle transmitting and receiving device includes one transmitting section, one transmitting antenna connected to the transmitting section, one receiving section, and one receiving antenna connected to the receiving section. Alternatively, the on-vehicle transmitting and receiving device includes one transmitting section, one receiving section, and one transmitting and receiving antenna connected to the transmitting section or to the receiving section in a switching manner.
Such conventional keyless entry apparatuses can be divided into two types in terms of their operations.
In a first type, on-vehicle transmitting and receiving apparatuses always transmit a request signal intermittently. When a user carrying a portable transmitting and receiving device come close to a vehicle and the portable transmitting and receiving device receives a request signal, the portable transmitting and receiving device transmits an answer signal in response to the request signal. When an on-vehicle transmitting and receiving device receives the answer signal, the locking section of each door of the vehicle is unlocked and the user can open and close each door.
In a second type, on-vehicle transmitting and receiving devices have a door-handle-contact detecting sensor near each door handle of vehicles. When a user carrying a portable transmitting and receiving device approaches a vehicle and contacts a door handle, an on-vehicle transmitting and receiving device transmits a request signal. When the portable transmitting and receiving device carried by the user receives the request signal, the portable transmitting and receiving device transmits an answer signal in response to the request signal. When the on-vehicle transmitting and receiving device receives the answer signal, the locking section of each door of the vehicle is unlocked and the user can open and close each door.
Therefore, the user can open and close any door without unlocking the locking section of each door of a vehicle by using the door key.
The conventional keyless entry apparatuses have an advantage that the user can open and close any door when the user carries a portable transmitting and receiving device and just approaches a vehicle or approaches the vehicle and touches a door handle. Since the locking sections of all the doors of a vehicle are unlocked when the on-vehicle transmitting and receiving device receives an answer signal which the portable transmitting and receiving signal sends in response to a received request signal, a malicious third party can get into the vehicle from a door, such as the door at the seat next to the driver""s seat, at the side opposite the side where the user is located, such as the driver""s side because it is difficult for the user to see the third party. This is not preferred in terms of crime prevention.
Especially in the conventional first-type keyless entry apparatuses, when the user approaches a vehicle and is located at a certain distance from the vehicle, for example, at a five-meter distance, even if the user cannot see the vehicle, a request signal and an answer signal are transmitted and received, and the locking section of each door is unlocked. Therefore, it is highly possible that the above-described incident happens.
In the conventional keyless entry apparatuses, when the user approaches a vehicle and is located at a certain distance from the vehicle, even if not the locking section of each door of the vehicle but the locking section of a truck is controlled, a request signal and an answer signal are transmitted and received as described above, and the locking section of the trunk is unlocked. Therefore, anybody can open the trunk until the user reaches the trunk, and this is not preferred either in terms of crime prevention.
The present invention has been made in consideration of the above-described technical background. Accordingly, it is an object of the present invention to provide a keyless entry apparatus for selectively controlling only a member to be controlled located closest to the user when the user approaches a vehicle and a request signal and an answer signal are transmitted and received.
Another object of the present invention is to provide a keyless entry apparatus for controlling such that, when the user approaches a vehicle, a request signal and an answer signal are transmitted and received, and the user touches the handle of the door specified by the answer signal, only the door can be selectively opened and closed.
One of the foregoing objects of the present invention is achieved in one aspect of the present invention through the provision of a keyless entry apparatus including an on-vehicle transmitting and receiving device mounted on a vehicle; and a portable transmitting and receiving device, wherein the on-vehicle transmitting and receiving device includes a plurality of antennas mounted correspondingly to members to be controlled of the vehicle, and a transmitting section which is connected to the plurality of antennas and which transmits a plurality of request signals having unique antenna IDs; the transmitting section transmits the plurality of request signals through the corresponding antennas; and when the portable transmitting and receiving device receives any of the transmitted request signals, the portable transmitting and receiving device transmits an answer signal which controls the member to be controlled corresponding to the antenna which transmitted the received request signal.
According to the keyless entry apparatus, the on-vehicle transmitting and receiving device includes an antenna and a transmitting section for each member to be controlled of a vehicle, a unique ID is assigned to each antenna, the on-vehicle transmitting and receiving device intermittently transmits the same number of request signals having different IDs as that of antennas, and when the portable transmitting and receiving device receives a request signal transmitted from the antenna closest to the portable transmitting and receiving device, the portable transmitting and receiving device transmits an answer signal which specifies the member to be controlled corresponding to the received request signal. When the on-vehicle transmitting and receiving device receives the answer signal, only the member to be controlled specified by the answer signal is controlled, and the other members to be controlled are not controlled. Therefore, the vehicle is effectively prevented from being used by a third party.
One of the foregoing objects of the present invention is achieved in another aspect of the present invention through the provision of a keyless entry apparatus including an on-vehicle transmitting and receiving device mounted on a vehicle; and a portable transmitting and receiving device, wherein the on-vehicle transmitting and receiving device includes a plurality of antennas mounted correspondingly to members to be controlled of the vehicle, a transmitting section which is connected to the plurality of antennas and which transmits a plurality of request signals having unique antenna IDs, and a door-handle-contact detecting section disposed at each door of the vehicle; the transmitting section transmits the plurality of request signals through the corresponding antennas; when the portable transmitting and receiving device receives any of the transmitted request signals, the portable transmitting and receiving device transmits an answer signal which controls the member to be controlled corresponding to the antenna which transmitted the received request signal; and when the on-vehicle transmitting and receiving device receives the answer signal, only if the member to be controlled specified by the answer signal is the locking section of any door and the door-handle-contact detecting section of the door corresponding to the answer signal outputs a contact detecting signal, the on-vehicle transmitting and receiving device unlocks the door.
According to the keyless entry apparatus, the on-vehicle transmitting and receiving device includes an antenna, each door has a door-handle-contact detecting section, a unique ID is assigned to each antenna, the on-vehicle transmitting and receiving device transmits the same number of request signals having different IDs as that of antennas, and when the portable transmitting and receiving device receives a request signal transmitted from the antenna closest to the portable transmitting and receiving device, the portable transmitting and receiving device transmits an answer signal which specifies the member to be controlled corresponding to the received request signal. When the on-vehicle transmitting and receiving device receives the answer signal, if the member to be controlled specified by the answer signal is the door closest to the portable transmitting and receiving device, and the user touches the handle of the door, only the locking section of the door is unlocked and the locking sections of the other doors are not unlocked. Therefore, the vehicle is completely prevented from being used by a third party.
The members to be controlled may include the locking section of each door and the locking section of a trunk in the vehicle.
In such a configuration, the locations of the members to be controlled in the vehicle are appropriately apart. Even when an antenna is disposed close to each member to be controlled, ranges in which request signals transmitted from the antennas can reach overlap a little.
It is preferred that the plurality of antennas be divided into two groups and the request signals be transmitted at different timing between the groups.
In this case, it is be possible that the transmitting section includes a plurality of transmitting units, and at least one of the transmitting units is shared by two antennas.
In such a configuration, when the plurality of transmitting units transmit request signals, the interference of the request signals is reduced and the request signals have high quality. When a plurality of transmitting units are shared by two antennas, the number of transmitting units to be used is reduced.
It is also preferred that the request signals be low-frequency signals.
In such a configuration, a range in which a transmitted request signal can reach is restricted. Therefore, the portable transmitting and receiving device which is relatively apart from the vehicle unpreparedly receives a request signal in reduced cases. The overlapping area of a zone in which a transmitted request signal can reach and a zone in which another transmitted request signal can reach is reduced.